1. Field of the Invention
This invention relates to staking grooves used to retain bearings and liner bushings within their receiving holes.
2. Description of the Prior Art
Staking grooves are a very common way of retaining a bearing or a bushing within a receiving hole. Commonly the bearing or bushing has formed within it adjacent its outer circumference a groove normally having an included angle of about 60.degree.. Once the bearing or bushing is inserted into its receiving hole, some sort of tool such as a staking anvil or a center punch is forced into the staking groove to bend over at least one of the webs of metal adjacent the staking groove in order to fold this web of metal over onto a corresponding receiving beveled surface machined into an appropriate location of the receiving hole. When the staking process is done correctly, the staking serves to retain the bearing or bushing within the receiving hole by means of this crimping or folding over action of the web of metal adjacent the staking groove. Insofar as is known, however, the staking grooves utilized in the past have all been of the so-called "Grumman" type characterized by the groove having walls which are at 60.degree. to one another. In installations of bushings or bearings which will encounter thrust loads parallel to the axis of rotation of the bearing, the Grumman groove is an inadequate retention means. This is because the relatively thick basal portion of the web of metal which is bent over does not bend as much as does the upper, thinner part of the web. This causes a radiused bend in the staked web which allows for a finite amount of creep or slippage between the outer surface of the bushing or bearing and the receiving hole. There is a clear need for an improved staking groove system in which this undesirable radiused staked web is eliminated.
The crimping or staking of the web in the staking groove can be accomplished by a number of different tools. For instance, center punches are commonly used for this purpose. More effective, however, is a specialized staking anvil which, in its normal configuration, comprises a hollow cylinder, one end of which is appropriately beveled such that when forced down into the receiving staking groove, the staking anvil will act to bend over and stake down the deformable web or webs of the staking groove in the bearing assembly or liner bushing. Unfortunately, unless the working end of the cylindrical staking anvil is exactly congruent to the configuration of the staking groove, the conventional staking anvil will work and chatter its way around, either resting predominately on the inside web of the staking groove or on the outside web of the staking groove and will not make complete contact with both web surfaces. This results in a less than desired staking action by the conventional staking anvil.